[Mac] Retain location bar focus on switching to fullscreen and back.

chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_controller.mm

Index: chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_controller.mm
diff --git a/chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_controller.mm b/chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_controller.mm
index f80e083fb15fb17e8d608eba1fa2eee3944f7475..6b553bbeb6dc3ffbfa6b67e4c07e9bba32254c8c 100644
--- a/chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_controller.mm
+++ b/chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_controller.mm
@@ -47,6 +47,14 @@ const CGFloat kShowFraction = 1.0;
   DCHECK(!inFullscreenMode_);
   inFullscreenMode_ = YES;
 
+  // If the location bar is the first responder, don't let the toolbar hide.
+  // This is a special signal to -mustShowFullscreenToolbar that the toolbar
+  // should remain visible during the transition to fullscreen.
+  if ([browserController_ locationBarHasFocus]) {
+    [visibilityLockController_ lockToolbarVisibilityForOwner:self
+                                               withAnimation:NO];
+  }
+
   [self updateToolbarStyleExitingTabFullscreen:NO];
 
   if ([browserController_ isInImmersiveFullscreen]) {
@@ -60,6 +68,11 @@ const CGFloat kShowFraction = 1.0;
         initWithFullscreenToolbarController:self
                         animationController:animationController_.get()]);
   }
+
+  // Let the location bar keep the toolbar locked in place from here on out
+  // (if it's the first responder).
+  [visibilityLockController_ releaseToolbarVisibilityForOwner:self
+                                                withAnimation:YES];
 }
 
 - (void)exitFullscreenMode {
@@ -132,6 +145,12 @@ const CGFloat kShowFraction = 1.0;
   if (!inFullscreenMode_)
     return NO;
 
+  // Check if the fullscreen toolbar controller wants the toolbar to remain
+  // visible.
+  if ([visibilityLockController_ isToolbarVisibilityLockedForOwner:self]) {
+    return YES;
+  }
+
   if (toolbarStyle_ == FullscreenToolbarStyle::TOOLBAR_PRESENT)
     return YES;